Occlusal design of implant denture
Because of the difference between implant denture and natural tooth, it should be treated differently in occlusal design. Based on different missing tooth sites and different soft and hard tissue conditions, the design of implant denture restoration varies greatly.
The repair methods of local missing teeth include implant-supported single crown, double-end bridge, single-end bridge and so on, and the repair methods of complete arch missing teeth include fixed denture and implant-supported overdenture. Different implant dentures have different characteristics in occlusal design. For example, single fixed denture supported by later dental implants:
First of all, the ideal force of the implant should be along the axial direction of the implant. So the question is, how to achieve the axial force of the implant?
If the single implant denture in the posterior region can achieve the buccal-lingual three-point jaw contact similar to that of natural teeth, it can also achieve the goal of axial transmission of jaw force.
However, unlike natural teeth, the motion of osseointegration implants is only 3-5 μ m (the normal movement of natural teeth can reach 25-100 μ m). Once the implant denture is lost at any point A, B, C in the process of use, the non-axial stress loading on the implant will be formed.
Therefore, for the posterior single implant denture, the safer maxillary contact design is to form a certain area of apical-oval fossa contact with the opposite jaw teeth, rather than A, B, C three-point contact.
The essence of apical-oval fossa contact is to enlarge the three points A, B and C into three sides A, B and C.
Can the axial transmission of jaw force of implant dentures in posterior teeth be solved by apical-oval fossa contact alone? How to design the occlusal contact of such an implant?
Regardless of whether it is correct to release the implantation site and direction, when our task is to repair such an osseointegration implant, can we achieve the goal of axial transmission of jaw force through a certain occlusal contact design?
The answer is maybe.
The ideal midline of the maxillary posterior dental implant should be facing the buccal tip-tongue oblique surface of the mandibular opposite tooth. When the maxillary implant is shifted no more than half of the cusp oblique to the palate, and the midline of the implant is opposite to the central fossa, we can give up the contact between the An and B sides of the central fossa of the maxillary teeth and the buccal tip of the mandibular teeth, and keep only the B and C contact between the palatal tip of the maxillary teeth and the central fossa of the mandible teeth, so as to realize the axial conduction of the force along the implant.
When the maxillary implant is shifted to the palatal side and the midline of the implant is opposite to the buccal slope of the tongue tip of the jaw tooth, it can be seen that the position of the implant can be designed as anti-jaw, and achieve stable A, B, C three-sided contact.
When the maxillary implant shifts more than one cusp slope to the palatal side, and the midline of the implant is facing the tip of the tongue, in addition to the reverse design, it is also necessary to give up the contact between the buccal tip of the upper tooth and the central fossa of the lower tooth to prevent the cantilever from being forced.